red eyed dude u mean the knight at the end of that castle wall??
just ignore him and the blue-eyed side is the way ahead,

i pretty much always keep my shield up (especially in dark narrow corridors)
once u lock-on to an enemy (R3) don't be afraid to back off or to the side (strafe dancing??) watching the timing of his attacks, and then strike back when they are vulnerable,

one thing to keep an out for is your stamina bar on the top left, this decreases for any action (R1, R2, X (roll, run)) and also when taking a hit to the shield,
so after each attack or defended hit, give urself a breather by backing off, letting go of shield so the stamina can regenerate again,

it's very tempting to try and sneak just one more attack, but that massively increases the risk of a counter-hit (even weak enemies find a way!!) and/or being stunned when u are blocking with too low stamina

i'm a knight so started with a sword, hope this is applicable to u too^__^*